ATF6 and diabetes mellitus: ER stress signaling is regulated by three major stress transducers located in the ER membrane, activating transcription factor 6 (ATF6), inositol‐requiring enzyme 1 (IRE1), and PKR‐like ER kinase (PERK), and has been implicated in diverse diseases such as cancer, type 2 diabetes mellitus (T2DM), and neurodegenerative and rheumatic diseases (Cnop et al., 2012; Navid and Colbert, 2017; Oakes and Papa, 2015).